How is the quality of your iPhone 5s low-light video?

Since I've gotten my iPhone 5s, I haven't taken a ton of video, but I've switched to video mode enough to know that I feel as if video quality isn't so great. After asking around and performing a quick internet search, it appears that I'm not alone either. Some people seem to have the issue, while others don't. Here are some sample shots of what I'm experiencing with low-light video...

The screenshots below are a comparison between my iPhone 5s and iPhone 5c in the exact same lighting conditions, same environment. At first I thought about getting my iPhone 5s swapped but upon testing two other iPhone 5s' in the house, they seem to both produce the same issue. The iPhone 5c doesn't seem to have it, even though I have seen some sketchy results here and there. I even tried in the above photo to find a better focus point on the 5s to change the exposure, it just wouldn't budge. Apple doesn't boast improvements in video quality for the iPhone 5s, just photo. Perhaps this is why?

I can't help but feel that the larger aperture, better sensor, and 64-bit processor in the iPhone 5s would help, not hinder the quality of video, even if there weren't improvements made specifically to benefit video capture. What do you guys think?

Here's more examples of iPhone 5s photo quality compared to video, in my experience:

I'm inclined to think this is a software issue since I'm seeing the problem on quite a few iPhone 5s', not just one or two. I'll be interested to see what you guys think and if you're having issues as well, so let us know!